The present invention relates to skylights formed from plastic sheets and more particularly to apparatus for making skylights from polycarbonate polymer sheets.
In the past, a variety of skylights have been provided which are typically formed from thin sheets of transparent plastic material which is clamped to a mold and vacuum formed. The molds are typically formed with a domed center portion, even though this is not necessarily a spherical shaped dome and which has a perimeter flange which may be attached to the roof of a house. Typically, skylights are attached either directly to a flat portion of a roof, or alternatively, attached to a raised area where the flat perimeter portion of the skylight is covered with flashing. It has also been suggested to provide skylights with self-flashing formed around the perimeter of the skylight. In recent years with the emphasis on energy, it has been suggested to have domes formed with an air space between a pair of domes or between the dome and a flat translucent plastic sheet to thereby entrap air to reduce the movement of heat through the skylight.
Prior art of this type can be seen in U.S. Pat. No. 3,127,699 for a self-flashing skylight unit, which shows a pair of domes forming an air space therebetween in one embodiment, and a dome mounted to a flat transparent sheet in a second embodiment, each to form a dead air space therebetween. Another doubled dome skylight can be seen in U.S. Pat. No. 3,455,073, which mounts a pair of domes together between a plurality of seals to thereby form a dead air space between the domes. Other twin dome type skylights can be seen in U.S. Pat. No. 3,111,786 for a Skylight and Ceiling Light Construction; and in U.S. Pat. No. 4,073,097 for an energy efficient skylight construction; in U.S. Pat. No. 3,417,527 for a skylight dome and in U.S. Pat. No. 3,417,522 and 3,434,250 for dual dome skylights. U.S. Pat. No. 2,858,734 has a skylight having a dead air space formed with special lenses, while U.S. Pat. No. 3,350,823 is an insulated skylight having dual domes filled with a core material. U.S. Pat. No. 3,012,375 has a combination skylight and ceiling light dome formed into one unit, while in U.S. Pat. No. 3,440,779, a pair of flat panels are used to form a skylight. Additional skylight construction can be seen in U.S. Pat. No. 3,983,669 for a skylight and frame; No. 3,461,625 for a self-flashing skylight curve construction; No. 3,473,276 for a domed roof light; No. 2,703,060 for a skylight construction; No. 2,610,593 for skylight construction; No. 2,693,156 for a skylight; No. 3,996,844 for an opening skylight of great stability; and No. 3,934,383 for a roof vent.
In U.S. Pat. No. 2,918,023 to Bettcher, a skylight is illustrated having an upper and lower dome with the lower dome reversed from the upper dome, and in one embodiment, has a transparent sheet connected therebetween to form double air spaces which are reinforced in different manners, as illustrated therein.